Two hypotheses will be tested. The first is that the release of AHCPR's Unstable Angina Guidelines will lead to increased adherence to key guideline recommendations in the management of hospitalized unstable angina patients. The second is that an educational intervention designed to improve guideline adherence will lead to better adherence than simple release of the guidelines in the community. Three kinds of data will be collected to support hypothesis-testing. First, medical charts will be abstracted to confirm the diagnosis of unstable angina and to collect data relevant to measurement of adherence to guidelines. A total of 5,500 charts will be audited in ten hospitals for a five-year period, 1993 through 1998. Because the AHCPR Unstable Angina Guidelines were published in May of 1994, data will be available for one year prior to their publication. Second, Medicare claims data will be used to identify patients with a discharge diagnosis of unstable angina and to provide data elements reported to HCFA, such as length of stay. Third, physicians will be surveyed to learn their knowledge and attitudes regarding the AHCPR Guidelines. The design of the study is described as quasi-experimental. It involves randomization to intervention or control of each member of five pairs of matched hospitals. Methods include the development of quantitative process-of-care indicators which measure adherence to key aspects of the guidelines in the management of hospitalized Medicare patients. These indicators will be based on clinical algorithms which are applied to computerized data abstracted from the 5,500 charts. Through use of customized software, the abstracted data will be linked to Medicare claims data. Five of the ten hospitals will be assigned to an educational intervention group that utilizes the HCFA approach. The intervention will disseminate the guidelines using local opinion leaders. As part of the intervention, hospitals will receive feedback on hospital-specific performance reflecting the period prior to the educational intervention, based on the computerized algorithms. The intervention itself will consist of CQI activities designed to increase adherence to the guidelines. Adherence to key aspects of the guidelines, as measured by the process of care indicators, will be the main outcome measures of the study. Data will also be collected on patient outcomes such as mortality, myocardial infarction rate, readmission rate, and length of stay. Technology use and expenditures for unstable angina patients in the ten hospitals over five years will also be measured. The relationships among adherence to various components of the guidelines, patient outcomes, and changes in these outcomes over a five-year period in intervention and control hospitals will be investigated.